Maintenance plan allows the landlord to define building specific maintenance actions schedule and create maintenance events for 3 years ahead. 

For that, go to Maintenance - Maintenance plan and choose the building You want to create a plan for. Create a new category, for example, ventilation system. Hint: it is wise to reuse already created categories for different buildings for further data collection.

After the category creation, the maintenance action should be created. Click on "Add maintenance action" and fill in all the required fields. Give the action the name, for example, Ventilation check, shortly describe the task and provide some instructions. If the work is required by law, You can tick the checkbox.
Define the occurrence of the action by choosing the frequency, pick the date and the duration of it. 
As a final step, choose an assignee - a service provider and tick the checkbox if You would like the provider to receive an order email before the start of the event automatically. By default, the order email comes 5 days before the event start. If You would like to change this setting, You can go to Settings - Email settings - Automatic emails - Service order email - Edit automation and change the automation settings according to Your preferences.

Having this setting activated helps the landlord to automate the process of sending out emails so that there are no worries worries about forgotten reminders of the upcoming maintenance event.

If You have added an agreement with a service provider, You can also add it to Your action and the maintenance events will be created only for the period of the agreement. Otherwise, the events will be created for the next 3 years. After the event has been completed, the next one will be generated automatically so that there is always a range of 3 years. 

Save the action and generated events will be displayed in the Calendar and as a list in Maintenance events tab!